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Dominik T, Mele A, Schurger A, Maoz U. Libet's legacy: A primer to the neuroscience of volition. Neurosci Biobehav Rev 2024; 157:105503. [PMID: 38072144 DOI: 10.1016/j.neubiorev.2023.105503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/09/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
The neuroscience of volition is an emerging subfield of the brain sciences, with hundreds of papers on the role of consciousness in action formation published each year. This makes the state-of-the-art in the discipline poorly accessible to newcomers and difficult to follow even for experts in the field. Here we provide a comprehensive summary of research in this field since its inception that will be useful to both groups. We also discuss important ideas that have received little coverage in the literature so far. We systematically reviewed a set of 2220 publications, with detailed consideration of almost 500 of the most relevant papers. We provide a thorough introduction to the seminal work of Benjamin Libet from the 1960s to 1980s. We also discuss common criticisms of Libet's method, including temporal introspection, the interpretation of the assumed physiological correlates of volition, and various conceptual issues. We conclude with recent advances and potential future directions in the field, highlighting modern methodological approaches to volition, as well as important recent findings.
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Affiliation(s)
| | - Alfred Mele
- Department of Philosophy, Florida State University, FL, USA
| | | | - Uri Maoz
- Brain Institute, Chapman University, CA, USA
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van Schie HT, Iotchev IB, Compen FR. Free will strikes back: Steady-state movement-related cortical potentials are modulated by cognitive control. Conscious Cogn 2022; 104:103382. [PMID: 35914430 DOI: 10.1016/j.concog.2022.103382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/15/2022]
Abstract
In psychology and neuroscience, opposition to free will has asserted that any degree of perceived self-control or choice is a mere epiphenomenon which provides no meaningful influence on action. The present research tested the validity of this conclusion by designing a paradigm in which the potential effect of self-monitoring on motor output could be investigated. Using a repetitive finger tapping task that evokes automatic patterns in participants tapping responses, we have obtained evidence that (1) participants may voluntarily reduce the predictability of their tapping patterns (2) by exercising cognitive control that (3) modulates response-locked steady-state movement-related potentials over primary and supplementary motor areas. These findings challenge the most radical accounts of the nonexistence of free will and instead provide support for a more balanced model of human behaviour in which cognitive control may constrain automatic response tendencies in response preparation and action execution.
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Affiliation(s)
- Hein Thomas van Schie
- Radboud University Behavioural Science Institute, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands.
| | | | - Félix René Compen
- Department of Psychiatry, Radboud University Nijmegen Medical Center, P.O. Box 9104 / 966, 6500 HE Nijmegen, The Netherlands; Radboud University Donders Institute for Brain, Cognition and Behaviour, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands.
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Bečev O, Mareček R, Lamoš M, Majchrowicz B, Roman R, Brázdil M. Inferior parietal lobule involved in representation of "what" in a delayed-action Libet task. Conscious Cogn 2021; 93:103149. [PMID: 34098153 DOI: 10.1016/j.concog.2021.103149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 03/22/2021] [Accepted: 05/05/2021] [Indexed: 11/28/2022]
Abstract
Intentional motor action is typically characterized by the decision about the timing, and the selection of the action variant, known as the "what" component. We compared free action selection with instructed action, where the movement type was externally cued, in order to investigate the action selection and action representation in a Libet's task. Temporal and spatial locus of these processes was examined using the combination of high-density electroencephalography, topographic analysis of variance, and source reconstruction. Instructed action, engaging representation of the response movement, was associated with distinct negativity at the parietal and centro-parietal channels starting around 750 ms before the movement, which has a source particularly in the bilateral inferior parietal lobule. This suggests that in delayed-action tasks, the process of action representation in the inferior parietal lobule may play an important part in the larger parieto-frontal activity responsible for movement selection.
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Affiliation(s)
- Ondřej Bečev
- Brain and Mind Research, CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic; Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, MU, Pekařská 664/53, 656 91 Brno, Czech Republic; National Institute of Mental Health, Topolová 748, 250 67 Klecany, Czech Republic.
| | - Radek Mareček
- Brain and Mind Research, CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Martin Lamoš
- Brain and Mind Research, CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Bartosz Majchrowicz
- Consciousness Lab, Institute of Psychology, Jagiellonian University, Ingardena 6, 30-060 Kraków, Poland
| | - Robert Roman
- Brain and Mind Research, CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Milan Brázdil
- Brain and Mind Research, CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic; Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, MU, Pekařská 664/53, 656 91 Brno, Czech Republic
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Sanford P, Lawson AL, King AN, Major M. Libet’s intention reports are invalid: A replication of Dominik et al. (2017). Conscious Cogn 2020; 77:102836. [DOI: 10.1016/j.concog.2019.102836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 11/26/2022]
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Verbaarschot C, Farquhar J, Haselager P. Free Wally: Where motor intentions meet reason and consequence. Neuropsychologia 2019; 133:107156. [DOI: 10.1016/j.neuropsychologia.2019.107156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/29/2019] [Accepted: 08/02/2019] [Indexed: 10/26/2022]
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Schwarz A, Ofner P, Pereira J, Sburlea AI, Müller-Putz GR. Decoding natural reach-and-grasp actions from human EEG. J Neural Eng 2019; 15:016005. [PMID: 28853420 DOI: 10.1088/1741-2552/aa8911] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Despite the high number of degrees of freedom of the human hand, most actions of daily life can be executed incorporating only palmar, pincer and lateral grasp. In this study we attempt to discriminate these three different executed reach-and-grasp actions utilizing their EEG neural correlates. APPROACH In a cue-guided experiment, 15 healthy individuals were asked to perform these actions using daily life objects. We recorded 72 trials for each reach-and-grasp condition and from a no-movement condition. MAIN RESULTS Using low-frequency time domain features from 0.3 to 3 Hz, we achieved binary classification accuracies of 72.4%, STD ± 5.8% between grasp types, for grasps versus no-movement condition peak performances of 93.5%, STD ± 4.6% could be reached. In an offline multiclass classification scenario which incorporated not only all reach-and-grasp actions but also the no-movement condition, the highest performance could be reached using a window of 1000 ms for feature extraction. Classification performance peaked at 65.9%, STD ± 8.1%. Underlying neural correlates of the reach-and-grasp actions, investigated over the primary motor cortex, showed significant differences starting from approximately 800 ms to 1200 ms after the movement onset which is also the same time frame where classification performance reached its maximum. SIGNIFICANCE We could show that it is possible to discriminate three executed reach-and-grasp actions prominent in people's everyday use from non-invasive EEG. Underlying neural correlates showed significant differences between all tested conditions. These findings will eventually contribute to our attempt of controlling a neuroprosthesis in a natural and intuitive way, which could ultimately benefit motor impaired end users in their daily life actions.
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Affiliation(s)
- Andreas Schwarz
- Institute of Neural Engineering, Graz University of Technology, Stremayrgasse 16/IV, 8010 Graz, Austria
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Libet’s experiment: A complex replication. Conscious Cogn 2018; 65:1-26. [DOI: 10.1016/j.concog.2018.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/21/2018] [Accepted: 07/06/2018] [Indexed: 11/20/2022]
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Khalighinejad N, Schurger A, Desantis A, Zmigrod L, Haggard P. Precursor processes of human self-initiated action. Neuroimage 2017; 165:35-47. [PMID: 28966084 PMCID: PMC5737384 DOI: 10.1016/j.neuroimage.2017.09.057] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 08/28/2017] [Accepted: 09/26/2017] [Indexed: 12/01/2022] Open
Abstract
A gradual buildup of electrical potential over motor areas precedes self-initiated movements. Recently, such “readiness potentials” (RPs) were attributed to stochastic fluctuations in neural activity. We developed a new experimental paradigm that operationalized self-initiated actions as endogenous ‘skip’ responses while waiting for target stimuli in a perceptual decision task. We compared these to a block of trials where participants could not choose when to skip, but were instead instructed to skip. Frequency and timing of motor action were therefore balanced across blocks, so that conditions differed only in how the timing of skip decisions was generated. We reasoned that across-trial variability of EEG could carry as much information about the source of skip decisions as the mean RP. EEG variability decreased more markedly prior to self-initiated compared to externally-triggered skip actions. This convergence suggests a consistent preparatory process prior to self-initiated action. A leaky stochastic accumulator model could reproduce this convergence given the additional assumption of a systematic decrease in input noise prior to self-initiated actions. Our results may provide a novel neurophysiological perspective on the topical debate regarding whether self-initiated actions arise from a deterministic neurocognitive process, or from neural stochasticity. We suggest that the key precursor of self-initiated action may manifest as a reduction in neural noise. Self-initiated action was operationalized in a novel perceptual decision making task. EEG variability decreased prior to self-initiated action. These findings could be accounted for by a leaky stochastic accumulator model.
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Affiliation(s)
- Nima Khalighinejad
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK
| | - Aaron Schurger
- Cognitive Neuroimaging Unit, CEA DRF/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France
| | - Andrea Desantis
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK
| | - Leor Zmigrod
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK.
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Weinberger S, Greenbaum D. Are BMI prosthetics uncontrollable Frankensteinian monsters? BRAIN-COMPUTER INTERFACES 2016. [DOI: 10.1080/2326263x.2016.1207495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Sara Weinberger
- The Zvi Meitar Institute for Legal Implications of Emerging Technologies, Radzyner Law School, Interdisciplinary Center, Herzliya, Israel
| | - Dov Greenbaum
- The Zvi Meitar Institute for Legal Implications of Emerging Technologies, Radzyner Law School, Interdisciplinary Center, Herzliya, Israel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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Verbaarschot C, Haselager P, Farquhar J. Detecting traces of consciousness in the process of intending to act. Exp Brain Res 2016; 234:1945-1956. [PMID: 26920393 PMCID: PMC4893062 DOI: 10.1007/s00221-016-4600-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/14/2016] [Indexed: 11/26/2022]
Abstract
An intention to act has different onsets when it is measured in different ways. When participants provide a self-initiated report on the onset of their awareness of intending to act, the report occurs around 150 ms prior to action. However, when the same participants are repeatedly asked about their awareness of intending at different points in time, the onset of intending is found up to 2 s prior to action. This ‘probed’ awareness has its onset around the same time as the brain starts preparing the act, as measured using EEG. First of all, this undermines straightforward interpretations about the temporal relation between unconscious brain states and conscious intentions and actions. Secondly, we suggest that these results present a problem for the view that intentions are mental states occurring at a single point in time. Instead, we suggest the results to support the interpretation of an intention to act as a multistage process developing over time. This process of intending seems to develop during the process of acting, leaving reportable traces in consciousness at certain points along the road.
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Affiliation(s)
- Ceci Verbaarschot
- Center for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, The Netherlands.
| | - Pim Haselager
- Center for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, The Netherlands
| | - Jason Farquhar
- Center for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, The Netherlands
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Reckoning the moment of reckoning in spontaneous voluntary movement. Proc Natl Acad Sci U S A 2016; 113:817-9. [PMID: 26772313 DOI: 10.1073/pnas.1523226113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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